Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
  • H01L31/1876—Particular processes or apparatus for batch treatment of the devices
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
  • H01L31/1876—Particular processes or apparatus for batch treatment of the devices
  • H01L31/188—Apparatus specially adapted for automatic interconnection of solar cells in a module
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/53—Means to assemble or disassemble
  • Y10T29/5313—Means to assemble electrical device
  • Y10T29/532—Conductor
  • Y10T29/53209—Terminal or connector
  • Y10T29/53213—Assembled to wire-type conductor

Definitions

• the present invention relates generally to thin film solar cells used for converting sunlight into electrical power, and more particularly relates to methods and equipment for interconnecting solar cells to form a photovoltaic module o string.
• the field of photovoltaics generally relates to multi-layer materials that convert solar radiation or sunlight energy into direct current (DC) electricity for the generation of electric power.
• These photovoltaic materials are commonly referred to as solar cells, and can be produced commercially in a thin-film configuration, such as by depositing one or more thin layers of photovoltaic material and supporting layers onto a substrate in a certain pattern and sequence.
• Thin film solar cells provide several advantages. One such advantage is that these compositions have a high cross-section for absorbing incident light. That is, photovoltaic layers that are very thin can capture a relatively high percentage of incident light. For example, in many thin film solar cell devices, photovoltaic layers may have a thickness in the range of from about 1 ⁇ to about 4 ⁇ .
• These thin layers allow devices incorporating these layers to be flexible.
• the characteristic flexibility of thin films further enables the solar cell material comprising numerous devices to be prepared in a continuous fashion, such as on a flexible web. This is in contrast to less flexible solar cells, such as those that comprise crystalline silicon, for example, which are typically fabricated and processed as discrete individual solar cells.
• a number of solar cells can be electrically and physically connected to each other in an arrangement that is referred to as a photovoltaic module or "string".
• Such modules or strings are designed to supply electricity at a certain voltage, where the electricity produced is directly
• modules can in turn be attached to each other to form an array.
• the larger the area of a module or array the more electricity that will be produced.
• These modules and arrays can be connected in either series or parallel electrical arrangements to produce desired voltage and current combinations.
• electrical connections can be made in series to achieve a desired output voltage and/or in parallel to provide a desired amount of current source capability.
• a semiconductor junction develops a photo- voltage, while the area and other parameters of the device determine the available current.
• Commercially available solar panels are therefore designed to have an appropriate area and arrangement to deliver a certain amount of power and optimize other application parameters.
• Photovoltaic arrays are often associated with buildings, where these arrays can be integrated into the building structure, mounted onto the building in some way (e.g., attached to the roof structure), or located separately from the building structure but connected by a cable or power supply to the building.
• arrays are built as a part of the construction of a new building, and in other cases, the arrays are retrofitted into existing buildings.
• roof tiles have been developed that incorporate photovoltaic cells, where these tiles are used instead of traditional roofing shingles.
• solar cells can be incorporated into wall panels of a building, such as panels that can be incorporated into the siding structure or that may be attached to existing siding materials.
• Such roof tiles and/or wall panels can be incorporated into both domestic and industrial buildings as a primary or secondary source of electrical power for that structure.
• interconnection process As part of the process of fabricating thin film solar cell modules or strings, several processing steps must be carried out to connect multiple solar cells to each other, which can be referred to as an interconnection process.
• interconnecting elements which can be wires or flat wires (which are also referred to herein and. known in the art as ribbons), for example, and solar cells in order to obtain mechanically robust solar cell strings that can be used in later processes that utilize those strings.
• This precise placement of wire ribbons relative to the solar cells also requires precise regulation of the dispensing of the conductive epoxy that functions as an adhesive. Precise control of mechanical tolerances is important to ensuring that the solar cell strings can easily be accommodated in downstream processes.
• Figure 1 is a perspective view of a solar cell interconnect system of the invention
• FIG. 1 is a front view of the solar cell interconnect system of
• FIG. 3 is a side view of the solar cell interconnect system of
• FIG. 4 is a top view of the solar cell interconnect system of
• Figure 5 is a perspective view of a ribbon reel handler
• Figure 6 is a perspective view of a dispense and cell interconnect module of the system of Figure 1 ;
• Figure 7 is a perspective view of a curing oven module of the system of Figure 1 ;
• Figure 8 is a perspective view of an interconnect conveyor system of the interconnect system of Figure 1 ;
• Figure 9 is a top view of an individual solar cell of the type that can be interconnected with other solar cells using the methods and systems of the invention.
• Figure 10 is a top view of an individual solar cell of the type illustrated in Figure 9, and further illustrating one exemplary adhesive application pattern;
• Figure 11 is a top view of a leading ribbon and showing an exemplary adhesive dispensing zone
• Figure 12 is a top view of an interconnect ribbon and showing an exemplary adhesive dispensing zone
• Figure 13 is a top view of an exemplary five-cell interconnected solar cell string of the invention.
• Figure 14 is a schematic illustration of five solar cells shown without a collection grid pattern and with only a single interconnection ribbon, trailing ribbon, and leading ribbon shown, for clarity of illustration;
• Figure 15 is a top view of a bottom pallet, in accordance with the invention.
• Figure 16 is a side view of an exemplary vacuum system for use in providing straight wire material to the adhesive dispensing stations.
• the present invention relates to the fabrication of interconnected solar cell assemblies using a "string and tab" type of approach, which requires precise placement of interconnecting ribbons and solar cells in a predefined configuration.
• systems and methods of the invention are provided for an automated solar cell string
• the interconnect equipment generally includes a bottom carrier (e.g., conveyor belt or roll or other element but preferably a pallet), at least one top carrier (preferably multiple top pallets), a robot for transferring top carriers (e.g., pallets), a transporting system (preferably a conveyor system for transporting pallet assemblies through an adhesive curing and or heating system), an adhesive dispensing system, a ribbon (e.g., a wire ribbon) feeding system, one or more vision systems, and a cell placement system for placing cells on the bottom carrier (e.g., bottom pallet), although all of these components are not necessary for every system.
• a bottom carrier e.g., conveyor belt or roll or other element but preferably a pallet
• at least one top carrier preferably multiple top pallets
• a robot for transferring top carriers (e.g., pallets)
• a transporting system preferably a conveyor system for transporting pallet assemblies through an adhesive curing and or heating system
• an adhesive dispensing system e.g., a ribbon feeding system
• the physical features of the carriers e.g., pallets
• interfacing mechanical engagement and alignment features for securing the pallets and alignment features such as pins or grooves for securing the ribbons and adhesive
• pins or grooves can provide for interfacing mechanical engagement and/or alignment features and adhesive curing for the solar cell assemblies.
• the manufacturing system of the invention can be referred to generally as a pallet-based photovoltaic string assembly system.
• a method of manufacturing electrically interconnected solar cell assemblies comprising the steps of: (a) providing a first photovoltaic cell; (b) positioning at least a first interconnect element in an alignment feature (e.g., a groove) of a top carrier (e.g., pallet) and facing a top surface of the first cell; (c) adhering the first interconnect element to a predetermined location on the top surface of the first cell, wherein a length of the first interconnect element extends beyond a trailing edge of the first cell; (d) positioning a portion of the length of the first interconnect element that extends beyond the trailing edge of the first cell in a first alignment feature (e.g., groove) of a bottom carrier (e.g., pallet); and (e) adhering at least a portion of the length of the first interconnect element that is positioned in the first alignment feature of the bottom carrier to a predetermined location on the bottom surface of a second cell, thereby
• Step (c) may further include applying adhesive on at least one of a predetermined location on the top surface of the first cell and a predetermined location on a surface of the first interconnect element
• step (e) can further comprise applying adhesive on at least one of a predetermined location on a bottom surface of the second cell and a portion of the length of the first interconnect element that is positioned in the first alignment feature of the bottom carrier.
• a solar cell module or string will often also desirably be provided with a leading ribbon and/or a trailing ribbon to provide for electrical connection of the module or string with other conductive elements within the module such as terminal bars and buss bars in order to utilize the solar power collected by the solar cell assembly.
• the method can further comprise the steps of: positioning at least one trailing element in an alignment feature (e.g., groove) of a top carrier (e.g., pallet) and facing a top surface of the final cell of the string; and adhering the at least one trailing element to a predetermined location on the top surface of the final cell, wherein a portion of each of the at least one trailing elements extends beyond a trailing edge of the final cell.
• an alignment feature e.g., groove
• a top carrier e.g., pallet
• the method can further include the steps of: positioning at least one leading element in an alignment feature (e.g., a groove) of a bottom carrier (e.g., a pallet) and facing a bottom surface of the first cell; and adhering the at least one leading element to a predetermined location on the bottom surface of the first cell, wherein a portion of each of the at least one leading elements extends beyond a leading edge of the first cell.
• an alignment feature e.g., a groove
• a bottom carrier e.g., a pallet
• a method of connecting leading and trailing elements to other conductive elements such as terminal or buss bars is provided, such that the connection occurs while the solar cells and ribbons are secured in place by the carrier assemblies (e.g., pallet assemblies).
• a system for assembling thin film solar cell interconnected strings.
• the system comprises cell transfer equipment, a lower carrier (e.g., a pallet)
• alignment features e.g., multiple grooves
• upper carrier system e.g., a plurality of upper pallets
• alignment features e.g., multiple alignment features
• a ribbon reel handler and unwind module 100 which generally includes a ribbon reel handler and unwind module 100, a dispense and cell interconnect module 200, a curing oven
• modules and equipment of the system 10 are generally identical
• certain components of the equipment modules can operate simultaneously such that solar cells may not be simply moving along a linear path through a system that includes sequential processing steps. That is, multiple operations can be occurring at least partially simultaneously in order to increase the throughput time for constructing and curing each solar cell string.
• the rolls of photovoltaic cells may be any photovoltaic cells in a flexible form. Examples include IB-IIIA chalcogenides (e.g., copper indium gallium selenides (CIGS), copper indium sulfide selenides (CISS) and the like), amorphous silicon, cadmium tellurides on flexible subtrates, and gallium arsenide cells.
• the photovoltaic cells can comprise a photovoltaic absorber layer that absorbs light energy embodied in the sunlight rays and then photovoltaically converts this light energy into electric energy.
• the absorber layer is preferably a chalcogenide-containing absorber region.
• the absorber can be a single integral layer or can be formed from one or more layers.
• the chalcogenide absorber layer can incorporate at least one IB-IIIB-chalcogenide, such as IB-IIIB- selenides, IB-IIIB-sulfides, and IB-IIIB-selenides-sulfides that include at least one of copper, indium, and/or gallium.
• these materials can be present in polycrystalline form.
• these materials can exhibit cross- sections for light absorption that allow the absorber to be very thin and flexible.
• an absorber layer may have a thickness in the range from about 1 ⁇ ⁇ to about 5 ⁇ , and more specifically can be in the range of about 2 ⁇ to about 3 ⁇ .
• CIGS materials with photovoltaic properties may be represented by the formula CuIn (1-x ⁇ Ga x Se ( -y) S y where x is 0 to 1 and y is 0 to 2.
• the copper indium selenides and copper indium gallium selenides can be used.
• the absorber layer may be formed by any suitable method using a variety of one or more techniques such as evaporation, sputtering, electrodeposition, spraying, sintering, and the like.
• the solar or photovoltaic cells discussed herein generally include a flexible substrate onto which multiple thin layers the photovoltaic materials and other active components have been deposited in a particular manner.
• the substrate may be formed from a wide range of flexible materials that allow the formation of a continuous photovoltaic element. These include polymers, metals, metal alloys, intermetallic compositions, paper, woven or non-woven fabrics, combinations of these, and the like.
• a conductive substrate such as stainless steel is used.
• a number of layers may also be included as part of the photovoltaic cell, including a backside electrical contact region, buffer region, and transparent conducting oxide (TCO) layer. Each of these regions can be a single integral layer or can be formed from one or more layers.
• the electrical contact layer may be formed from a wide range of electrically conductive materials, including one or more of Cu, Mo, Ag, Al, Cr, Ni, Ti, Ta, Nb, W, combinations of these, and the like. Conductive compositions incorporating Mo may be used in an illustrative embodiment. When based upon chalcogenide materials, the cell can be provided with a heteroj unction structure in contrast to silicon-based semiconductor cells that have a homoj unction structure.
• a heteroj unction may be formed between the absorber region and the TCO layer buffered by a buffer layer.
• An optional window layer also may be present.
• Each of these regions can be a single integral layer or can be formed from one or more layers.
• the buffer layer generally comprises an n- type semiconductor material with a suitable band gap to help form a p-n junction proximal to the interface between the absorber region and the buffer layer.
• Exemplary buffer layer materials include CdS or ZnS, while exemplary TCO layers can be indium tin oxide or aluminum zinc oxide. Zinc oxide can be used as an optional window layer.
• each layer depends on the choice of materials and on the particular application process chosen for forming each layer.
• the individual cells may be individually formed or may have been cut from a flexible substrate comprising multiple photovoltaic articles adjacent to each other along the length of the material.
• a photovoltaic or solar cell 20 is illustrated in Figure 9, which includes a substantially planar and rectangular material piece having a top surface 22, an opposite bottom surface 24, a leading edge 26, and a trailing edge 28 that is generally opposite the leading edge 26.
• Each cell 20 may be identically or similarly sized to other cells that will be provided to the interconnect system 10, although it is understood that the individual cells may be at least slightly different from each other.
• the top surface 22 of each cell 20 is generally configured to include a collection structure or grid comprising one or more relatively narrow conductive strips or buss lines 30, which may be
• buss lines 30 may be adjacent to or contiguous with a plurality of collector strips or fingers 32 that extend generally parallel to the direction of the leading and/or trailing edges 26, 28. These collector strips 32 can be considerably thinner than the buss lines 30.
• the collector strips 32 and buss lines 30 are used together for the collection of electrons, as is known in the industry for photovoltaic processes.
• the collection grid can be formed from a wide range of electrically conducting materials, but most desirably are formed from one or more metals, metal alloys, or intermetallic compositions. Exemplary materials include one or more of Ag, Al, Cu, Cr, Ni, Ti, or the like, which can be used individually or in combination with each other.
• the buss lines 30 and collector strips 32 can be made of a conductive silver ink layer.
• the collection grid has a dual layer construction including nickel and silver.
• Figure 10 is another top view of the cell 20 of Figure 9, further illustrating areas of dielectric or electrically insulating material 34 generally at the leading edge 26 of the cell 20 adjacent to the buss lines 30.
• the electrically insulating material 34 can be applied to one or both of the top and bottom surfaces 22, 24, and/or can be applied along the leading edge 26 of the cell 20.
• One exemplary pattern or dispense zone for the adhesive that will be applied in the steps described below is also illustrated in Figure 10 and is designated as reference number 36.
• This illustrated adhesive dispense zone 36 extends from a point adjacent to the electrically insulating material 34 and along each buss line 30 toward the trailing edge 28, but terminates prior to reaching trailing edge 28, thereby leaving a space between the trailing edge 28 and the end of the adhesive zone 36.
• the adhesive is used to form an electrical connection between the top or bottom surface of a cell and an interconnect element.
• the adhesive is preferably an electrically conductive adhesive such as a conductive epoxy.
• Solar cells 20 which may be of the type illustrated in Figures 9 and 10, can be provided in batches or stacks and manually or automatically provided to an unloading station, which is generally part of the cell
• the solar cells 20 can be provided to the interconnect system in bins or stacks, which may
• the cells provided in the bins can be manually loaded
• a vision camera 204 can be used to pick individual cells from the bins and place in an inspection area.
• system 202 can then be used to guide an industrial robot 204 in the precision pick-up and placement of the photovoltaic cell onto a flattop vacuum
• system 202 includes a camera that takes a picture of the top surface of the cell, which conveys information regarding the exact orientation of the cell to the robot 204 so that the robot can pick it up and placed it on the conveyor
• the cell can then be moved along the conveyor 206 so that
• adhesive can be dispensed or applied via adhesive dispensing heads 208 onto the top surface of the photovoltaic cell 20.
• Three of such adhesive dispensing heads 208 are illustrated, which can simultaneously apply adhesive to three separate areas, such as the adhesive dispense zones 34 described above.
• the adhesive dispensing heads 208 may comprise dispensing units that provide the adhesive in the form of a generally linear array of individual beads or globules. When the ribbons and pallets are placed onto the arrays of beads of adhesive, the discrete adhesive areas will spread toward other discrete areas until they connect with each other to make a continuous or relatively continuous adhesive strip.
• the adhesive dispensing heads are jet dispensers, in one exemplary embodiment.
• adhesive can be applied to one side of a ribbon as that ribbon is being unwound from a spool 102 of the ribbon reel handler and unwind module 100, as is illustrated in Figure 5.
• the ribbon can be a flat wire, such as a copper wire, or more preferably a tin-plated copper wire for example, although other materials may be used for the ribbon.
• three separate ribbon spools 102 are provided in order to supply the three ribbons that are needed for placement on the three adhesive dispense zones 34.
• ribbons of three different types and lengths are needed for producing the final interconnected assembly (e.g., interconnection ribbon, leading ribbon, or trailing ribbon, as will be described below).
• the adhesive is applied to the adhesive dispense zones 42 and 44 on the leading and interconnecting ribbons 40 and 41, respectively, as shown in Figures 11 and 12.
• this exemplary embodiment includes applying adhesive to the adhesive dispense zones 34 on the solar cell 20 and the adhesive dispense zones 42 and 44 on the leading and trailing ribbons 40 and 41 , it is understood that adhesive can alternatively or additionally be applied to the ribbons that will be placed on those adhesive dispense zones 34, which will generally coincide with the buss lines 30 and/or applied to the bottom of cells in the predetermined locations which the leading and interconnecting ribbons will be positioned.
• the ribbons can be provided with a precursor that allows the ribbon to be adhered to the top and bottom surfaces of the solar cells during or after placement of the ribbons in the grooves of the pallets.
• ribbons coated with a pressure sensitive adhesive may be used that form a bond with the surfaces of the cells when pressure is applied, for example when the top pallets are placed on the cell.
• the ribbons may comprise a solder coating that allows bonding of the ribbon to the top and bottom surfaces of the cells via the application of heat.
• the ribbon unwinding operation can further include cutting the ribbon into certain predetermined lengths, depending on the intended use for that ribbon in an interconnected solar cell assembly (e.g., interconnection ribbon, leading ribbon, or trailing ribbon, as will be described below).
• the cutting operation can take place either in the ribbon reel handler and unwind module 100, or in the cell interconnect module 200.
• the interconnect module 200 can be provided with a vacuum fixture, such as fixture 220 illustrated in Figure 16.
• the fixture 220 includes a plate 226 having a protrusion 222 with a distal groove 224 and a plurality of vacuum holes (not shown), which can help to ensure that the ribbon is secured in a precise orientation as it is unwound from the spool and moves across the groove 224.
• the ribbon reel handler and unwind module 100 also comprises mechanisms for removing camber from the ribbons as they are introduced into the interconnect system 200. This ensures that the final interconnected assembly can be , manufactured within the specified tolerances.
• the ribbon straightening mechanism comprises a plurality of rollers through which the ribbons are fed prior to cutting to reduce the camber of the ribbon material.
• the ribbon straightening mechanism comprises an electric motor-driven spool unwind that is actuated by positioning feedback that is provided by a moving "dancer" roller placed onto an unspooled section of the ribbon. This dancer roller can provide tension to the ribbon material as it moves through the mechanism. After the ribbon passes under or past the dancer roller, various roller-type material straightening mechanisms can be used to correctly position the ribbon as it comes out of the unwind module 100.
• precision servo and pneumatic controlled actuators can be used in conjunction with a robot to interconnect multiple solar cells into a string using a relatively large bottom pallet with multiple top pallets.
• a bottom pallet 240 is illustrated in Figure 15, which can be sized to accommodate an entire string of interconnected solar cells during the interconnection process.
• the width of the grooves in the bottom pallet are approximately equal to the width of the ribbons and provide a mechanism for ensuring that the multiple ribbons across the width of the cells are parallel within 0.1 mm tolerance.
• the pallets can further provide mechanical engagement and alignment features that assist in accurate assembly of the pallets and that also assist in maintaining accuracy of the pallet alignment during conveyance of the assembly through subsequent processing steps (e.g., oven curing).
• the bottom pallet further comprises notches in the edge of the pallet that enable clamping of the pallet for holding it in position during fabrication of the interconnected assembly.
• the bottom pallet may also consist of a plurality of holes for application of vacuum to secure the cells in place during assembly of the interconnected string, or can alternatively or additionally include other features for securing the cells in place.
• One upper pallet is typically provided for each of the individual cells, wherein the width of each upper pallet is approximately equal to the width of the individual solar cells.
• the top pallets comprise a top plate with an extension that comprises a groove.
• the groove can be configured with a plurality of holes for application of vacuum for securing ribbons during ribbon transfer, or can alternatively or additionally include other features for securing the ribbons in a designated location, such as clamps, magnets, and the like.
• the width of each of the grooves in the top pallet is approximately equal to the width of each of the ribbons.
• the interconnecting ribbons can be present in the grooves of both the bottom pallet and the top pallet, thereby providing a mechanism for ensuring that the multiple ribbons across the width of the cells are parallel within a specified tolerance (e.g., 0.1 mm tolerance).
• the depth of the grooves is configured to be approximately equal to the thickness of the ribbon, plus the desired final thickness of the adhesive.
• FIG 14 schematically illustrates various ribbons that can be used with solar cells in constructing a solar cell string including five solar cells.
• a first interconnect ribbon 64 is positioned in a groove of a top pallet so that it is facing the top surface of the solar cell 60.
• Adhesive is applied to either the top surface of the first cell (e.g., along one of the buss lines), along a. portion of a surface of the ribbon 64, or on both of these surfaces.
• the ribbon and top surface of the cell are brought into contact with each other, with a portion 66 of the ribbon 64 extending beyond a trailing edge 68 of the cell 60.
• the portion 66 is positioned in a groove of a bottom pallet so that it is facing a bottom surface of the second solar cell 62.
• Adhesive is applied to either the bottom surface of the second cell, along a portion 66 of the ribbon 64, or on both of these surfaces.
• the ribbon portion 66 and the second cell 62 are then brought in contact with each other to adhere the ribbon to the bottom of the second solar cell 62.
• This process can be simultaneously performed with three ribbons, for example, as would be needed to interconnect the cells along three buss lines of adjacent solar cells.
• the process of interconnecting two adjacent solar cells can be repeated also for attaching the other adjacent cells to each other (e.g., attaching the second and third solar cells, the third and fourth cells, etc.).
• one end of the array includes a trailing ribbon and another end of the array includes a leading ribbon.
• These ribbons are provide for electrical connection of the module or string with other equipment in order to utilize the solar power collected by the solar cell array.
• the leading ribbon 70 is positioned in a groove of a bottom pallet and facing the bottom surface of the first cell 60. Adhesive is applied to either the bottom surface of the first cell, along a portion of the leading ribbon 70, or on both of these surfaces. The leading ribbon and the bottom surface of the first solar cell 60 are then brought into contact with each other to adhere the leading ribbon 70 to the solar cell 60.
• a portion of the ribbon 70 is positioned to extend beyond a leading edge 67 of the solar cell 60.
• the trailing ribbon 78 is positioned in a groove of a top pallet and facing a top surface of the cell 76. Adhesive is applied to either the top surface of the cell 76, along a portion of the trailing ribbon 78, or on both of these surfaces. The trailing ribbon 78 and the top surface of the cell 76 are then brought into contact with each other to adhere the trailing ribbon 78 to the cell 76.
• a portion of the ribbon 78 is positioned to extend beyond a trailing edge 80 of the cell 76.
• the entire interconnected string and their corresponding top and bottom pallets are transported through an oven, such as an infrared curing oven module 300 illustrated in Figure 7, in order to cure the adhesive.
• the oven may be provided with a series of infrared lamps, for example, which can have same or different intensities in the different zones.
• the oven zones can be designed to provide the optimum curing conditions for the particular adhesive that is used and it is contemplated that the intensity is variable so that it can be adjusted for different adhesives and or substrates onto which the adhesive s are applied.
• the curing temperature of the adhesive is monitored and controlled using feedback from temperature sensors that measure the temperature of the pallets via reflected infrared energy.
• the pallet system with interconnected solar cells will move in a first direction 302 through the oven until it reaches one end, and then a transfer conveyor or interconnect conveyor system 400 of Figure 8 will move the pallet system to the other side of the oven so that it can travel in an opposite direction 304 and back toward the cell interconnect module 200.
• the conveyor system 400 includes a first conveyor section 410 and a second conveyor section 420.
• the conveyor system 400 is a transfer conveyor that is utilized to send the pallets back through the oven. While in this embodiment, the conveyor system 400 is external to the oven because some components are not resistant to the oven temps, it is contemplated that the components are instead heat-resistant so that the conveyor can be positioned entirely or partially inside the oven.
• the interconnect system could comprise of a second interconnect module 200 at the end of the oven module 300, or an offload module at the end of the oven module 300.
• an industrial robot of the interconnect module 200 can remove the top pallets and position them for use in another interconnect assembly operation.
• a robot is also used to offload the complete and cured solar cell string from a bottom pallet, which is heated and thermally stabilized, to an operator offload station.
• the solar cell string can then be stacked or otherwise stored for transport to another location, such as for incorporation of the solar cell strings into a solar roof panel, for example.
• another location such as for incorporation of the solar cell strings into a solar roof panel, for example.
• the system is configured such that the strings move through the oven in only one direction. In this case, the oven will have a longer footprint and means would need to be provided for transporting the pallets back to the cell interconnect module 200 for use in subsequent operations.
• the interconnect system may also be configured with a system for attachment of additional electrically conductive elements to the ends of the leading and trailing ribbons.
• the conductive elements may include buss bars or terminal bars and other conductive elements that may be required to connect the interconnected solar cell assembly to external circuitry.
• the leading ribbons are connected to a first terminal bar, while the trailing ribbons are attached to a second terminal bar at the opposite end of the interconnected solar cell assembly.
• the first terminal bar and second terminal bar are electrically connected to each other. Possible methods of attachment of the leading and trailing ribbons to other conductive elements such as terminal bars may include soldering and welding. In an exemplary embodiment, the connection process is carried out via laser welding.
• the attachment of conductive elements can occur while the pallets are still in place with the interconnected assembly, such as following the completion of the interconnected string or following the curing process, while the cells and ribbons are secured in place by the pallet assemblies. This enables the final interconnected assembly including terminal bars to be manufactured within specified tolerances.

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• 2011
  • 2011-07-29 US US13/810,356 patent/US9065008B2/en not_active Expired - Fee Related
  • 2011-07-29 EP EP11741065.4A patent/EP2599129A2/en not_active Withdrawn
  • 2011-07-29 WO PCT/US2011/045822 patent/WO2012016103A2/en active Application Filing
  • 2011-07-29 CN CN201180037291.6A patent/CN103053032B/zh not_active Expired - Fee Related

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